Handwritten pen-on-paper signatures have been the basis of contracts in commerce for hundreds of years. One of the reasons is that the handwritten signature and the document on which it is applied are forever bound together by the ink being on the paper. Another advantage is that the signer can keep a copy or duplicate original of the contract to deter fraud.
However, the main difficulty encountering handwritten signatures is that the identity of the signatory cannot easily be ascertained when the document has been signed without witnesses. How can the signature applied on the document be authenticated? In other terms, how can a party having the singed document between his hands ascertain that the signature applied on the document has been written by the pretended signatory and not someone else?
The traditional remedy to this problem is to verify the identity of the signer by a trained forensic document examiner who is skilled in the art and science of signature character analysis, and who can testify, be qualified, and be cross-examined in a court of law if required.
If the signed document is an administrative document related to given administrative authority (such as a financial institution), another traditional remedy is to keep a model signature of the person in his administrative file with the administrative authority, and then use human judgement to compare the handwritten signature with the pre-registered model signature of the pretended signatory. However, since this method is based on human judgment, it is often object to human judgement errors which make it unreliable. It is usual for an administrative representative to commit a judgement error in comparing the signatures, thus resulting in approving a false signature or rejecting an authentic one. A judgement error can in certain situations involve legal liability of the administrative representative if, intentionally or by negligence, he rejected a signature that was authentic and caused a prejudice to the person by refusing to process the administrative document.
Recent developments in the field of data processing resulted in developing special technologies for authenticating a handwritten signature. Mainly, these technologies comprise capturing a handwritten signature, converting it to a digital format and using data processing utilities for comparing the captured signature with a pre-registered signature of the user. In addition of being complex and high costly, these technologies proved to be unreliable in certain circumstances.
From the electronic documents perspective, the continuing development of electronic document storage and retrieval as well as data processing and computer technologies has created a recognized need to an inclusion of legally effective signatures for creating legally binding electronic records.
The same authentication problem occurs for handwritten signatures applied on electronic documents. Early systems addressing this need utilized a simple image of a signature (such as a bit map) being affixed to a document as a picture of a signature. This approach had the disadvantage that the bit map image of the signature is difficult to verify as being directly from the hand of the signer, in that little if any dynamic data is present. Also, an image of a signature can easily be scanned from an existing document or record and improperly inserted into a document as a forgery.
Later systems included computer algorithms for verifying a signature prior to the user being able to sign an electronic document. Problems with this method include potential for errors in the verification algorithm, and the inability to demonstrate the accuracy of verification of a signature to a layperson or in a court of law. Further, the signatures are typically not transportable to systems having different algorithms without loss of data precision.
For example, U.S. Pat. No. 5,544,255 to Smithies et al. discloses a computer-based system for capturing and verifying a handwritten signature of an electronically stored document by capturing the signature and storing a set of statistical measurements in a signature envelope that can contain a checksum of the document. The measurements can include shape, number of pen strokes, total line length, average stroke length, number of acceleration and deceleration maxima events, the overall time taken to complete the signature, and the pen down time. The system can also contain a database of known signature measurement templates to be compared with a submitted signature to produce a similarity score. This system illustrates the main limitations of traditional systems for authenticating handwritten signatures. In fact, according to the system provided by Smithies, the first problem is that the signature envelopes cannot be verified by a forensic document examiner using traditional methods. Besides, the signature envelopes are not readily transportable to future systems, being based on arbitrary measurement statistics of the handwritten signatures. Also, the signature envelopes are ineffective to the extent that they omit information originally contained in the handwritten signature itself. Moreover, the system is highly complex, costly and slow due to the overall process of comparing signatures.
On the other hand, there are areas where use of electronic devices for typing information is unpopular, non-convenient or inaccessible. For example, in the legal world, lawyers and judges are known to be very classical people who prefer to handwrite information using a conventional paper format document rather than typing information using electronic devices. Judges are generally not ready to replace the classical way of handwriting notes by electronic means for typing information. Lawyers usually have a plurality of active files, where each file is associated with a particular mandate related to a particular client. Lawyers handwrite information related to their files in various occasions, for instance, in the frame of a legal consultation, a meeting with a witness and in the frame of taking personal notes on specific aspects of the file. Also, lawyers frequently handwrite information in connection with their client files in the courthouse, for instance in order to note a hearing date, a name of a judge and the terms of minutes or a judgement stated by a judge. In the same way, judges are assigned specific litigation files and generally take notes in various occasions in connection with their files, for instance, in the frame of taking notes during a trail and an interlocutory hearing.
In the medical field, doctors usually handwrite information on paper format documents of various natures, such as medical prescriptions and personal diagnosis notes associated to their patients. Because it is generally time consuming to photocopy or otherwise data process handwritten information using conventional methods, medical documents (ex. prescriptions) handwritten by doctors are sometimes handed to patients without keeping a copy thereof inside the patient file. This situation can create traceability problems of the patient medical history.
In general, handwritten paper format documents are generally indexed and classified in paper format files for future reference. Physical files can occupy a huge storage space and are vulnerable to accidents (such as fire) and fraudulent attempts (such as burglary). It is also common nowadays to scan and store in computer databases all handwritten paper format documents. However, this process of archiving handwritten information a posteriori is expensive and time consuming since it requires time and human resources for scanning and classifying the documents.